It would be good if when modelling parts, objects (surfaces/solids/Parts/Assemblies) could be derived in for reference purposes only.
This way tools such as projecting cut edges would update in a sketch between parts. At the moment if an intersection between parts is projected to a sketch this does not update. And if the part was for reference only you would not end up with extra unwanted solid bodies.
Then when creating the finished .idw, or inserting the part into the assembly the derived reference does not come through.